You're choosing a program, not a life. In Canada you apply to a specific program (Computer Science, Engineering, Commerce), but switching programs within a faculty is common and many schools let you take courses outside your program. A Grade 9 direction is just a hypothesis — treat it as one. What matters is picking courses and activities that keep real options open. The subject you can't avoid: math. Math is the one course that gates the most programs — engineering, computer science, commerce, sciences, and math itself all require Grade 12 advanced functions and often calculus. If you're not sure yet, keep math strong. It preserves more options than any other single decision. Use grade 9–10 to test, not decide. The best way to choose is exposure: take the intro courses, join the clubs, do the summer programs. Try a coding club and a debate team. Do a science fair and a DECA competition. The activities you stick with are better signals than any personality quiz — and the Majors Explorer here shows you the admission tiers and career paths behind each option so you can compare what's realistic. When to actually commit. By Grade 11, start narrowing to two or three programs so your Grade 12 course selection and extracurriculars line up. By the fall of Grade 12, you should know your application list. Programs are more forgiving of late clarity than students fear, but the prerequisite courses for competitive programs aren't — check each program's requirements before choosing Grade 12 electives.